If all Americans had equal access to the best preventive care currently available somewhere in the country, roughly 20% to 40% of premature deaths from the five leading causes of death could be avoided, CDC researchers calculated.

Every year, about 895,000 Americans under the age of 80 die as a result of heart disease, cancer, chronic lower respiratory diseases, stroke and accidents, government data show. But many of them didn’t have to.

To figure out how many people fit into that category, the researchers calculated the mortality rates for each of those five causes of death in each of the 50 states plus the District of Columbia. Then they looked for the three states with the lowest rates in each category and averaged them. That average was used as the best-case scenario.

Next, the researchers applied those ideal mortality rates to each state and calculated how many people under the age of 80 would have died of heart disease, cancer, respiratory diseases, stroke and accidents. The difference between the ideal and actual mortality rates represented deaths that could have been prevented, the researchers said. (The analysis was restricted to people under the age of 80 because the actual life expectancy in the U.S. is about 79, the researchers said.)

When they were done crunching the numbers, they found that 91,757 Americans die unnecessarily of heart disease each year. Another 84,443 die prematurely of cancer, 28,831 die early because of chronic lower respiratory diseases, 16,973 are killed by preventable strokes, and 36,836 die as a result of unnecessary accidents.

Put another way, if all of the states had mortality rates as low as they are in the ideal states, about 34% of heart disease deaths, 21% of cancer deaths, 39% of respiratory disease deaths, 33% of stroke deaths and 39% of deaths due to accidents could be avoided.

To make that happen, Americans need to exercise more, eat better, lose weight, quit smoking, use sunscreen and wear seat belts in cars and helmets when riding bicycles or motorcycles. They also need to work with their doctors to reduce their cholesterol, control their blood pressure and keep their Type 2 diabetes in check, among other things, the researchers advised.

The researchers said there was no way to estimate the overall number of Americans who die prematurely from those five causes of death. “A person who avoids death from heart disease might then be exposed to a higher risk for dying from injury or cancer,” they wrote. But better prevention would surely save lives overall, they said.

In 2010, these five leading causes of death accounted for 63% of all deaths in the U.S. For the sake of comparison, the next five leading causes accounted for only 12% of total deaths.

The results were published Thursday in the CDC's Morbidity and Mortality Weekly Report.